Trauma Heater overload

Okta said:
Gel batteries should be capable of taking a hammering from time to time. A leisure battery reading of 13V means nothing if the solar is active, the solar controller will raise the voltage but could be sending two thirds of three fifths of sod all charge into the batteries.
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Keep us informed it’s good to see what the end result is and what the problem was 👍
 
MykCamper said:
Just booked my van into Todds at Lostock Hall, my local Truma specialist, engineer thinks that a circuit board is going on the blink, with the info I relayed.
Will post the results next week! :=)
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Ok, that sounds to me like the gas governor is not modulating between high flame and off, and the fan is trying to distribute the additional heat.
The flame should regulate by temperature inside the annular shell. It is going out on overheat eventually.
Could be the pcb, a heat probe, or the gas governor/valve. Be careful you don’t boil the water in the water jacket, too. Just run it for short periods until fixed.
When it gets too hot you can turn the heating off so the gas goes off, and run the fan only on vent, to dissipate the build-up of heat, and cool the unit quicker.

I presume you can’t plug into EHU and use it on electric until it is sorted.
 
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That's very interesting, it explains the rapid heat build up.
Back home now but ran it today up to 15°C and everything was as normal.
Very little drain on the Leisure batteries, over a 2 hour run.
TR5 said:
Ok, that sounds to me like the gas governor is not modulating between high flame and off, and the fan is trying to distribute the additional heat.
The flame should regulate by temperature inside the annular shell. It is going out on overheat eventually.
Could be the pcb, a heat probe, or the gas governor/valve. Be careful you don’t boil the water in the water jacket, too. Just run it for short periods until fixed.
When it gets too hot you can turn the heating off so the gas goes off, and run the fan only on vent, to dissipate the build-up of heat, and cool the unit quicker.

I presume you can’t plug into EHU and use it on electric until it is sorted.
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MykCamper said:
That's very interesting, it explains the rapid heat build up.
Back home now but ran it today up to 15°C and everything was as normal.
Very little drain on the Leisure batteries, over a 2 hour run.
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I know on gas, the burner runs with a bit of a roar initially, then it dies down to a much smaller flame, and as it reaches temp it goes off, refiring when it cools somewhat. The fan usually only runs at high speed when the difference of the set temp and the ambient temp is great, and reduces as it gets nearer the set temp, like the flame does. I think the fan is controlled by the latent heat in the unit, so if it's over hot it tries to compensate.
Another thought - how are the hob and oven gas flames, if these are too high as well, perhaps the gas governor from the bottles has failed to regulate properly. Are they refillable gas bottles, has the 80% cut-off failed, and are over full? All worth checking!

Let us know of the outcome, for future reference.
 
You really should check both the voltage and the current the Truma is drawing.
A cheap multimeter is all you need, but be aware that a multimeter is not designed for long-term monitoring of current. Check the current draw from time to time, not continuously.
Although it is possible that the Truma is faulty, I'd guess that it is 100 times as likely that you have a problem with your batteries, the wiring or the charging.
Look for the cheap fixes and the likely faults before looking for unlikely, expensive ones.
 
Geek said:
You really should check both the voltage and the current the Truma is drawing.
A cheap multimeter is all you need, but be aware that a multimeter is not designed for long-term monitoring of current. Check the current draw from time to time, not continuously.
Although it is possible that the Truma is faulty, I'd guess that it is 100 times as likely that you have a problem with your batteries, the wiring or the charging.
Look for the cheap fixes and the likely faults before looking for unlikely, expensive ones.
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I agree. The repairer could fit expensive new parts before you find out that there was a problem with the battery.
 
Silly thought. Do you have an inverter or similar, such that the combi is running of 240v via inverter and LBs?
No way should 2x150AH batteries drop to 11v under 4.5 or 6.5A loading that quickly.
If the heater had a fault and was pulling 20A+ on 12v then it'd get to 11v eventually, but after many hours - and, one would hope, blow the fuse.
(So even faulty PCB should blow the fuse at high current draw)
Some facts missing here I think
Or batteries totally shot!
 
Okta said:
Unless the batteries are knackered.
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Agree - thats what I meant by "Or batteries totally shot!"
Its either that or some other info is missing from the puzzle.
 
As promised, the results from Todds MH's diagnostics.
A fuse had blown on one of my leisure batteries!.
A new 15 amp fuse was fitted as opposed to the 10amp that I was advised to use, all the rest of the electrics were checked out with no faults found.
A £75 peace of mind Bill, as I had a mice infestation last winter, which destroyed the heater control cable.
 
Is that fuse in line with the battery terminal? 10A or 15A seems quite low for that. Well, 10A does, at least. If you have two batteries wired in parallel, perhaps 15A in each makes sense.

If the fuse is for the power to the Truma, 10A or 15A seems way too high. It should never exceed 7.5A.

The point of a fuse is to stop the wire overheating, and if the wire was only able to carry 10A or 15A, that seems quite low.
 
Mmm - that does not explain the symptoms you told about the Combi overheating, and the fan going berserk!

Those symptoms are more concerning than a low battery reading, in my opinion. I would keep a close watch on the unit, and if these
re-occur, get the gas controld checked out pdq.
 
It does explain them to an extent. The burner gets things nice and hot, then the voltage drops and it can't carry on dissipating the heat.
Yes, keep an eye on it to be sure it is all working properly now, but unless and until it is known to be faulty, leave well alone.
 
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